Installing a Heat Pump During a Renovation: The Right Time, Neither Too Early nor Too Late
The sofa was still under its plastic covering when our technicians arrived in Saint-Aimé. It is a detail that says a great deal about how this project was carried out: the homeowners had called us before putting the furniture back, but after painting. That is exactly the right window, and it is narrower than most people think.
Too early in a renovation, the indoor unit collects drywall sanding dust in its heat exchanger and cross-flow fan—a type of dirt that cannot be cleaned with a cloth and will require a complete coil wash within two years. Too late, and heavy furniture must be moved, a finished floor protected, holes drilled above an already-filled closet, and the cleanest routing options abandoned because the wall has been closed up.
We installed a GREE FreeMatch R32 2-Head Wall-Mounted Heat Pump here, with an outdoor unit GWHD(18)ND6MO, one head in the room shown in the photograph and a second in the main living area.
A Wall-Mounted Head in a Small Room: The Opposite Constraint to What You Might Expect
The room shown in the photograph is compact. The indoor unit is installed on the narrow section of wall above the door frame, in the corner, with a smooth ceiling and a nearby bulkhead. Three decisions are behind this seemingly ordinary location.
Sizing Down
The natural instinct in a small bedroom is to choose the smallest unit in the catalogue and consider the matter settled. The real risk lies elsewhere: in a room smaller than 12 m², even the smallest head in a multi-zone system is often oversized. A 9,000 BTU/h unit in a properly insulated 10 m² bedroom provides far more capacity than needed. The unit then drops to its minimum modulation level, reaches the setpoint, and starts alternating between minimum operation and shutdown.
What we do in these cases: we favor the smallest available indoor unit, set it to continuous low-speed ventilation rather than automatic mode, and accept a lower but constant temperature difference. A small room is controlled through stability, not power.
Return air above a door
A wall-mounted unit draws air in through the top and front. Installed directly above a door frame, it risks two things: drawing in corridor air directly when the door is open, and ending up too close to the ceiling. We maintained the manufacturer’s required return-air clearance and shifted the unit a few centimeters toward the corner rather than centering it over the door—an aesthetically pleasing centered placement would have put the return intake directly in the door’s airflow.
Noise at night
In a living room, 40 dB(A) goes unnoticed. In a bedroom 2.4 m from the bed, it can be heard. We systematically program night mode and disable the front light display when the indoor unit serves a bedroom. Homeowners should not have to search for this function in the manual three weeks later.
The GWHD(18)ND6MO outdoor unit
| Feature | Value |
|---|---|
| Connectable indoor units | 2 |
| Rated cooling | 5,275 W — 18,000 BTU/h |
| Cooling modulation | 7,300 to 19,800 BTU/h |
| Rated heating | 5,275 W — 18,000 BTU/h |
| Heating modulation | 7,300 to 18,100 BTU/h |
| SEER2 | 21 |
| HSPF2 | 10 |
| EER2 | 12.5 — COP 3.9 W/W |
| Heating range | -30 °C to 24 °C |
| Cooling range | -30 °C to 48 °C |
| Refrigerant | R32, 900 g pre-charged |
| Outdoor airflow | 1,354 ft³/min |
| Outdoor sound pressure (high speed) | 54 dB(A) |
| Power supply | 208/230 V — MCA 14.5 A — MOCP 20 A |
| Pre-charged piping / maximum total length | 10 m / 40 m |
| Maximum elevation difference | 15 m |
| Weight / dimensions | 35.5 kg — 822 × 550 × 352 mm |
| Certification | ENERGY STAR |
Two values deserve the attention of anyone comparing quotes.
The outdoor sound level of 54 dB(A) is the lowest in the FreeMatch range. On a village lot where houses are close together, this is not a cosmetic detail: it determines whether your neighbor notices the unit or not.
The HSPF2 of 10 indicates seasonal heating performance. It is the figure subsidy programs look at, far more than the SEER2 that salespeople highlight.
The job, step by step
Protection first. Film on finished surfaces, drop cloths on the floor, and a HEPA-filter vacuum within reach. In a freshly painted house, a technician who sets up a ladder without protection leaves marks that no one accepts.
Marking and validation. The exact position was marked with tape and confirmed with the homeowners before any drilling. We never skip this step, even when the location seems obvious.
Wall detection. Locating the studs, the wiring for the ceiling-recessed fixture, and the wall-light box. The pass-through hole was positioned between two studs, with a 5° downward slope toward the outside for the gravity drain.
Routing. Refrigerant lines, condensate drain, and communication cable grouped in a white outdoor raceway, with continuous elastomeric insulation along the entire length and no exposed insulation joints.
Outdoor unit. A wall bracket anchored to the structure, vibration-isolating pads, and 50 cm of clearance beneath the unit for snow and defrost water. In Saint-Aimé, as throughout rural Montérégie, a unit installed too low can end up submerged in February.
Evacuation. Nitrogen pressure testing, evacuation to below 500 microns, and a documented decay test before opening the valves. The total length of the two circuits was under the 10 m precharged, so no refrigerant was added.
Commissioning and training. Night-mode settings, display shutoff, a demonstration of filter removal and washing, delivery of the documentation, and same-day warranty registration: 10 years on parts, extended to 12 years with proof of installation.
R32 in a Small Space
R32 replaces R410A because its climate impact is significantly lower. It is classified as A2L, meaning it is mildly flammable, which makes a check mandatory in small rooms: the minimum room volume based on the circuit charge. This calculation is precisely where a compact bedroom stops being a mere formality.
With 900 g precharged across two circuits, the margin was comfortable, and we documented it in the file. The factory-supplied A2L leak sensor included with the FreeMatch completes the setup: it locks out the system and starts the dispersion ventilation in the event of an anomaly. We also apply our standard practices everywhere: flare fittings tightened to the specified torque with a torque wrench, no flaring above a heat source, and the safety label left in place on the unit.
Errors We See in Renovation Projects
Our teams cover Montreal, Laval, Longueuil, the North Shore, and the South Shore, and the same scenarios keep recurring when the heat pump is installed at the wrong stage of the project:
- Unit installed before the drywall was finished. The heat exchanger fills with fine dust. Performance drops from the first season, and the customer blames the unit.
- Through-wall hole drilled by another trade. Approximate diameter, no slope, and no sleeve. Condensation water eventually ends up in the wall insulation.
- Non-dedicated electrical circuit. A head connected to a circuit shared with the lighting: the breaker trips, the unit restarts, and unexplained error codes appear.
- Location chosen by the general contractor without consultation. We have already redone installations where the head blew directly onto a bed, one metre from the pillow.
- Filters never cleaned after the renovation. Even when well protected, a unit commissioned at the end of a renovation should have its filters washed for the first time after one month.
Grants and eligibility
The FreeMatch R32 is ENERGY STAR certified with an HSPF2 of 10, placing it in the categories generally targeted by Quebec programs supporting high-performance heat pumps as a partial replacement for electric heating. The criteria, amounts, and application periods change, and we refuse to quote a figure without verifying it. We confirm eligibility at the time of the estimate, based on the conditions actually in effect that day, and provide the detailed invoice required by the programs.
What the homeowners told us during the follow-up visit
The comment we hear most often after an HVAC installation at the end of a renovation is not technical: it is about how clean the site was. In this case, the remark was that the outdoor line-hide followed the trim alignment exactly and that nothing had been left to redo.
At AirGreen, we prefer to get involved early in the renovation planning, even if that means returning to install the unit later. A line-set route decided before the wall is closed always produces a better result than an improvised solution afterward. In Saint-Aimé, the surrounding municipalities of the Pierre-De Saurel RCM, or Greater Montreal, our team assesses the building, the construction sequence, and the existing heating system before recommending a model.